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delhanty

1,230 karma · joined April 12, 2014

https://x.com/delhanty

Moderate countabilist

Making DOG’s ModeLer (#DOGML)

dogml.eth - expiration date: 2072.09.14 at 17:07 (UTC+09:00)

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delhanty··on Why Erdős Problems Are Falling to AI
It seems that AIs are really good at finding counterexamples now.

Even if progress by AIs in proving conjectures lags, it seems likely that AIs collectively will, in the next few years, find counterexamples to nearly all the Erdős (and other) conjectures that are actually false and also provably false.

That means we will able to assume that nearly all the remaining conjectures are either true or undecidable.

Surely, that's good for folks who just want to know where the truth boundaries in mathematics lie.

It's obviously causing a lot of soul-searching amongst professional mathematicians.

Arguably, they should have given less weight for the last 100 years to Hardy's view in 'A Mathematician's Apology' [0]:

> It is a melancholy experience for a professional mathematician to find himself writing about mathematics. The function of a mathematician is to do something, to prove new theorems, to add to mathematics, and not to talk about what he or other mathematicians have done.

Rota takes a much more balanced view in 'Indiscrete Thoughts' [1].

"Problem Solvers" take Hardy's view:

> ... The mathematical concepts required to state mathematical problems are tacitly assumed to be eternal and immutable. Mathematical exposition is regarded as an inferior undertaking. ...

While for "theorizers":

> Mathematical exposition is considered a more difficult undertaking than mathematical research.

If professional mathematicians can reinvent themselves, there will be plenty of work left to do to explain the results of AIs to other humans.

There probably needs to be a new career path into professional pure mathematics other than doing novel research in a PhD.

[0] https://en.wikipedia.org/wiki/A_Mathematician%27s_Apology

[1] https://ncatlab.org/nlab/show/Gian-Carlo+Rota

https://ncatlab.org/nlab/show/Gian-Carlo+Rota

delhanty··on Peter Sarnak – The Riemann Hypothesis [video]
2026-04-15 (10 days ago) Millennium Prize Problems Lecture posted yesterday on YouTube - watched 10 minutes so far - seems good level for HN - non-trivial but also no need to be a specialist in analytic number theory
delhanty··on Gerd Faltings, who proved the Mordell conjecture, wins the Abel Prize
> Mordel's conjecture implies as a special case that for all n>=4 there are only a finite number of solutions to Fermat's equations with relative prime numbers

I just learnt that fact from Wikipedia's article on Mordel's conjecture (now Faltings' theorem), was curious whether the theorem could be strengthened to obtain a full proof of Fermat’s Last Theorem (FLT) that is genuinely different from the Taylor–Wiles proof (or its later variants) and so asked an AI (in this case Grok via Twitter).

Grok correctly told me "no it's not possible", but then surfaced (as an aside) a nice expository article on the Taylor–Wiles proof by Faltings from AMS notices in July 1995, which I thought I'd share here:

https://www.ams.org/notices/199507/faltings.pdf

delhanty··on The Shape of Inequalities
Oh, these are really nice Andrei! Thanks for posting them.
delhanty··on Biconnected components
Thank you for the reply - appreciated.
delhanty··on Biconnected components
For the vertex biconnected components can you say how your implementation compares technically with Boost Graph library's `biconnected_components` and `articulation_points`?

https://www.boost.org/library/latest/graph/

https://www.boost.org/doc/libs/latest/libs/graph/doc/biconne...

Am I correct to suppose both are C++ implementations of Tarjan's algorithm?

delhanty··on Rasterizer: A GPU-accelerated 2D vector graphics engine in ~4k LOC
Thank you very much for that concise explanation.
delhanty··on Rasterizer: A GPU-accelerated 2D vector graphics engine in ~4k LOC
Congratulations!

Can you say how the it's similar and how it's different to superficially similar sounding work?

(1) https://github.com/linebender/vello , dual Apache/MIT, by Raph Levien et al

(2) https://sluglibrary.com/ , proprietary, by Eric Lengyel (Terathon)

delhanty··on Dropbox Passwords Discontinuation
> They introduced a feature that took me hours and hours to disable (the file not downloaded until you try to open it thing). One bit of documentation pretty much lied about turning it off. Turned out it had to be disabled in more than one place.

Are you able to say what the relevant settings are? (I would like to be able to do that too ...)

delhanty··on Why I left my tech job to work on chronic pain
As someone who has been mitigating and managing chronic pain for 25 years, with respect IMO your expectation is unrealistic.

There isn't a "solution" - you're looking at a life-long mitigation and management strategy that will not be "brief".

The time commitment typically goes up as one ages. I could spend 40 hours a week on nutrition, exercise and relaxation if I was trying to optimize for chronic pain reduction.

But then nothing else would get done.

delhanty··on History of CAD
>Becoming a book publisher wasn’t on my bingo card when I started Shapr3D. Yet here we go! For now, it’s only available to select customers—but if there’s enough interest, we’ll make it accessible to the public. The book spans 860 pages and weighs approximately 3 kg—just as heavy as CAD is.

Become a select customer of Shapr3D and their CEO István Csanády might send you one.

https://twitter.com/istvan_csanady/status/188829861216722566...

delhanty··on History of CAD
Seeing as David Weisberg's "History of CAD" is trending today I submitted "History of Unigraphics" by 3 of the original Unigraphics 7 dwarfs.

Edit: Unigraphics X SDRC became the system we know today as Siemens NX

It came out at the end of 2024 - these guys must all be around 80 by now.

https://news.ycombinator.com/item?id=43169194

delhanty··on Unigraphics, 1974–2001
Seeing as David Weisberg's "History of CAD" is trending today, I submitted "History of Unigraphics" by 3 of the original Unigraphics 7 dwarfs.

The article came out at the end of 2024 ... these guys must all be around 80 by now.

Edit: Unigraphics X SDRC became the system we know today as Siemens NX

delhanty··on Show HN: Hestus – AI Copilot for CAD
"fully constrained" means that there are no degrees of freedom left so that there are only a finite number of valid solutions, which are then consequently disconnected in the space of possible solutions.

DCM then chooses one valid solution that it believes is "close" to initial supplied positions/directions/radii etc for the geometry.

delhanty··on Show HN: Hestus – AI Copilot for CAD
Good luck guys! I watched the video on YT - hopefully will get around to trying the Fusion 360 add-in at some point.

Does the current add-in use AI at all?

What is your plan when, in the event of you getting some traction, Autodesk etc. copy you innovations into the main product?

As per my other comments [1][2], I worked on this area at D-Cubed and Solidworks from 1995 to 2002. Feel free to connect with me via twitter DM @delhanty [3].

[1] https://news.ycombinator.com/item?id=41440016

[2] https://news.ycombinator.com/item?id=41440150

[3] https://twitter.com/delhanty

delhanty··on Show HN: Hestus – AI Copilot for CAD
> Wonder if the 2D sketch experience is much better in Onshape, NX, Catia, etc?

Well those systems and pretty much all of the mechanical CAD industry is built upon D-Cubed's DCM, so I'd expect the behaviour to be the same.

If I was creating a new 3D CAD system from scratch now I'd probably license Parasolid eventually, but I'd pass on DCM.

I don't want to dump on D-Cubed and John Owen though. I have huge respect for him and the company he created. This is technical criticism with the benefit of hindsight.

delhanty··on Show HN: Hestus – AI Copilot for CAD
> And if this add-in becomes popular, Autodesk can trivially release something that has the same functionality, built into Fusion 360 by default. And, as you are no doubt painfully aware, the Fusion API can be limiting.

This is always the problem with add-ins like this as a business - you're essentially doing free market research for the application vendor.

delhanty··on Show HN: Hestus – AI Copilot for CAD
> The Fusion sketch solver is badly compromised, it can't do more than two or so simple successive Tangent relations without bugging out. And, my experience with Solidworks is the same, not sure if this is still true.

In my experience of building a sketcher at D-Cubed for a consultancy client (1995-2000) on top of D-Cubed's DCM, this is because DCM's curves (which are unbounded BTW) are not directed so that there are lots of erroneous solutions to attempting to constrain G1 chains of tangent bounded curves. For example the Apollonius Problem [1][2] of 3 tangent circles/lines has 2^3 = 8 solutions. IMO if John Owen had chosen directed curves for DCM then dragging configurations of tangent circles would be more stable.

I'll end with a quote from the Preface of Julian Lowell Coolidge's 1916 "A Treatise on the Circle and the Sphere" [3]:

> Among the cartesian theorems there is a sharp sub-division between those where the radius is looked upon as essentially signless and those where a positive or negative radius is allowed.

[1] https://mathworld.wolfram.com/ApolloniusProblem.html

[2] https://observablehq.com/@d3/apollonius-problem#

[3] https://en.wikipedia.org/wiki/A_Treatise_on_the_Circle_and_t...

delhanty··on Show HN: Hestus – AI Copilot for CAD
> I've been using parametric CAD (Pro/E / Creo, Solidworks, and Onshape) for 30+ years.

True - I implemented the first Solidworks Autodimension sketch as a contractor around 2002 based upon earlier work that I'd done for a consultancy client at D-Cubed in the late 1990s. I'm sure it could be improved with AI and a large data set of sketches though.

> Solidworks tries to help with this in the form of cycling through what it thinks are the most likely constraints to remove and then re-solving the sketch. It's OK, but that sort of tool could be better.

I agree it could be better. The behavior with under-constrained sketches depends on D-Cubed's DCM, and I seem to recall they were rather floppy. It seems kind of ridiculous to make users jump through the hoops of making sketches fully constrained once they've added the constraints they care about.

delhanty··on Stripe's Monorepo Developer Environment
>Some caveats: It’s been nearly five years, and I have no doubt that I have misremembered some of the specific details, even though I’m confident in the overall picture. I’m also certain that Stripe has continued evolving and I make no claim this document represents the developer experience at Stripe as of today.

Are there any more recently ex-Stripe folks here willing and able to comment on how Stripe's developer environment might have evolved since the OP left in 2019?

delhanty··on Creatine improves physical function and body composition in older adults
Creatine and caffeine possibly have a negative interaction - search PubMed for papers - eg

https://pubmed.ncbi.nlm.nih.gov/26219105/

I’m very slow and stiff in the mornings and I drink a lot of black coffee to mitigate that.

Then, late afternoon, perhaps 6 to hours later, I take my creatine monohydrate for the day just before my ocean swim.

delhanty··on Microplastics and Nanoplastics in Atheromas and Cardiovascular Events

  DOI: 10.1056/NEJMoa2309822
  Date: 2024-03-07
  Publication: N Engl J Med 2024
  Volume: 390
  Pages: 900-910
delhanty··on Microplastics and Nanoplastics in Atheromas and Cardiovascular Events
via The Guardian

https://www.theguardian.com/environment/2024/mar/06/microsco...

which at least had a link to the original paper.

delhanty··on Microplastics and Nanoplastics in Atheromas and Cardiovascular Events
Abstract

BACKGROUND

Microplastics and nanoplastics (MNPs) are emerging as a potential risk factor for cardiovascular disease in preclinical studies. Direct evidence that this risk extends to humans is lacking.

METHODS

We conducted a prospective, multicenter, observational study involving patients who were undergoing carotid endarterectomy for asymptomatic carotid artery disease. The excised carotid plaque specimens were analyzed for the presence of MNPs with the use of pyrolysis–gas chromatography–mass spectrometry, stable isotope analysis, and electron microscopy. Inflammatory biomarkers were assessed with enzyme-linked immunosorbent assay and immunohistochemical assay. The primary end point was a composite of myocardial infarction, stroke, or death from any cause among patients who had evidence of MNPs in plaque as compared with patients with plaque that showed no evidence of MNPs.

RESULTS

A total of 304 patients were enrolled in the study, and 257 completed a mean (±SD) follow-up of 33.7±6.9 months. Polyethylene was detected in carotid artery plaque of 150 patients (58.4%), with a mean level of 21.7±24.5 μg per milligram of plaque; 31 patients (12.1%) also had measurable amounts of polyvinyl chloride, with a mean level of 5.2±2.4 μg per milligram of plaque. Electron microscopy revealed visible, jagged-edged foreign particles among plaque macrophages and scattered in the external debris. Radiographic examination showed that some of these particles included chlorine. Patients in whom MNPs were detected within the atheroma were at higher risk for a primary end-point event than those in whom these substances were not detected (hazard ratio, 4.53; 95% confidence interval, 2.00 to 10.27; P<0.001).

CONCLUSIONS

In this study, patients with carotid artery plaque in which MNPs were detected had a higher risk of a composite of myocardial infarction, stroke, or death from any cause at 34 months of follow-up than those in whom MNPs were not detected. (Funded by Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale and others; ClinicalTrials.gov number, NCT05900947. opens in new tab.)

delhanty··on CSS for printing to paper
> but then based on my personal experience as print media designer the likes of InDesign are full of various special tricks (and language-specific, too)

That seems to concur with an informative article by AtaDistance from 2019 that I read the other day [0]:

> ...

> The result was InDesign 1.0 J which shipped in early 2001. InDesign J was the first, and only, major software application developed outside of Japan that followed the Japanese Industrial Standard (JIS) X4051 typesetting and composition specification (the kumihan “bible”) and traditional Japanese print production methods.

> I have covered some basics of Japanese layout before, but a review is helpful for first time readers. I’ll use a mix of my material and McCully’s presentation to explain.

> ...

> Western created DTP layout is graphics-driven and calculated by margins and font baselines. The western baseline typography model and font metrics is how PostScript and OpenType fonts, and all layout engines evolved. Adobe was well acquainted with the shortcomings of their own font technology and InDesign J got around the problems by adding proprietary Kanji virtual body font metrics and Japanese line break algorithms. None of this exists as an open standard that benefits everybody.

> That is fine for InDesign and print production, but web layout and typography via CSS is an entirely different world. There are 3 huge obstacles for good vertical Japanese typography on the web:

> * No font metrics for virtual body/em-box glyph space placement: everything has to be accomplished with baseline metrics

> * No reliable space control

> * No reliable line breaks

[0] https://atadistance.net/2019/04/26/the-state-of-css-japanese...

delhanty··on I Read All 59 of Warren Buffett's Annual Letters. These Are the Best Parts
https://archive.is/sNdnr
delhanty··on ArXiv now offers papers in HTML format
> If you are familiar with ar5iv, an arXivLabs collaboration, our HTML offering is essentially bringing this impactful project fully “in-house”. Our ultimate goal is to backfill arXiv’s entire corpus so that every paper will have an HTML version, but for now this feature is reserved for new papers.

IIRC, ar5iv was created on his own initiative by Deynan Ginev

https://twitter.com/dginev/status/1736792316675825981

and it seems that he has worked tirelessly to fix nearly all of the edge cases during the collaboration.

This project creates huge value to humanity so Deynan is to be heartily thanked.

delhanty··on Modern Pascal is still in the race (2022)
> C is almost LR(1),

Does that include the C preprocessor?

Somehow, I recall someone here (maybe it was user walterbright) suggesting that implementing a C preprocessor was a lot of work - maybe months - so one might consider using Facebook's MIT licensed preprocessor:

https://github.com/facebookresearch/CParser

delhanty··on Dramatic rise in cancer in people under 50
My only point was that it’s misleading to compare power.

I don’t have an opinion on whether mobile phone usage is more or less likely to cause cancer than working in a radio station.

delhanty··on Dramatic rise in cancer in people under 50
Your analysis doesn’t account for the inverse square law.

That is, wouldn’t we want to compare the radiant flux rather than the power?

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